First, may I suggest that you determine whether your D-104 already has that amplifier. Later D-104s manufactured for solid state rigs had an FET amp such as Don suggests built into the base. You turn the mic over and remove a few screws to see if it has the amp. It uses a 9V battery that is in the base as well.
The earlier ones that O.T.s like Don and I remember, had no amp and were used with the high-impedance (50K ohm to 100K ohm) input impedance of a vacuum tube pre-amp. If yours has the amp, all you need do is put in a fresh battery and then adjust the gain pot, which you will find in the base as well, for the desired amount of gain. 73, Ron AC7AC -----Original Message----- Alan, The 4 pin vs. 8 pin is not your only problem. For pin to pin connections, I suggest you consult G4WFW microphone connection database, it is quite helpful. The D-104 microphone element is quite high impedance, and some have suggested simply using a series resistor to mitigate the high vs. low resistance microphone impedance situation, I would suggest that a simple FET stage could solve the problem. The D-104 mic feeds the gate of the FET and the output is taken from the source (or drain). There was a web reference to the Heil FET amplifier that was recommended, but I have lost it. I have it on my hardrive and will send it to Alan in a separate email. -- the reflector will not accept html nor any other resential 73, Don W3FPR ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
